Chemically resistant containers



Filed April 15, 1957 INVENTOR.

v I. MOORE JVW A T TORNEJS 2,914,169 CHEMICALLY RESISTANT "CONTAINERSVernon L. Moore, Bartlesville, Okla., assignor to Phillips PetroleumCompany, a corporation of Delaware Application April 15,1957, Serial No.653,035 "3 Claims. "(c .*205* 's4 i This invention relates to improvedchemically resistant,

lined containers or'tanks; In one aspect, the invention relates tocontainers particularly adapted "for the storage of "fuels, especiallyrocket fuels'containing' amines. In another aspect, 'itgrelates to ,amethod for producing a container which is especially suitable for the"storage offuels. p v Containers or tanks formed of metal "or glassoften [prove to ;be unsuitable for storing and handling many fiuidsbecause-such rnaterialssometimes have a tendency to attack'themetalor'glass. The-literature describes the Euse of polyethylene as a liningmaterial to protect containersagainst attack" from stored materials.However, it has been found that conventionalpolyethylene, e.g.,polyethylene produced "by the usual high pressure methods, is not inallcases a suitable lining material, particularly when the'containersare to be used for the stora ge of certain fuels. For example;conventional. polyethylene when used as a-lining materialhasbeen found*to besubject to swelling and a weight gain when in contact with ifuelscontaining. amines. I It-is;'an"object"of this iiivention, therefore,top'rovide a novel, chemically resistant, lined container which is ;notstibjectto the disadvantages of conventional containers.

Another obiect of this invention is'to provide a tank or container whichis particularly suited for the'storage of rocket fuelsgparticularlyfuelscontaining amines. Another object of the invention is to provideamethod for producing "a chemically resistant, lined container which isparticularly adapted for the storage of fuels.

Other and further objects and advantages of the invention will becomeapparent to those skilledin the art upon consideration of the.accompanying disclosure. It'has nowbeen 'discovered that an improvedtank or container for the storage-and handlingof fluids is produced ifcertainnovel polymers ofethylene, having prop- 2,914,169 Patented Nov.24, 1959 ICC 035, 5; 25 0. The softening'point' or therpolym'er willvary with the particular polymer used, increasing as the g deusity andthe crystallinity of the polymer increases. Generally the softeningpoint is above about 250 F preferably-in the approximate range of 250 to300 F., and is several degrees, e.g., about 10 F., higher than themelting point of the polymer. The polymers often have an inherentviscosity of at least 0.8, preferably an inherent viscosity betweenabout 1.2 and about 10, as determined for -a solution of 0.2 gram ofpolymer in cc. of tetralin at130" C.

Polymers of ethylene having the above-described prop- 'ertiesare-preferably produced in the method described in jthefcopending US.Patent application of J. P. Hogan and R. L. Banks,'Se'rial No. 573,877,filed March- 26, 1956,;new US. Patent 2,825,721 (1958). Thus, solidethylenepolyiners'suifablefor use in this invention can be obtained'byconta'cting ethylene with a catalyst comprisin'g, asan essentialingredient, chromium oxide, preferabiy including a substantial amount ofhexavalent chromium, a described in the aforementioned application.Thechromium oxide is ordinarily associatedwith "selected from the groupconsisting of silica, alumina, Zirconia, and thoria. The temperature forthe polymerization reactionis usually in the range of about 100 to 500F,, with a tempera'ture in the range of 150 to 375 F. beingeften-preferredfor the polymerization ofethylene. "Thet'iolyineriza'tion is frequently conducted with the 30" 'be'm aintainedin the'liquid phase and is inert under'the polymerization conditions.Suitable hydrocarbons are .parafiins or cycloparafiins, for example,normalheptane, 2,2,4-trime'thylpentane, cyclohexane and'methyleyclothylenefin "admixture "with a hydrocarbon which can hexane."A continuous slurry-type reaction technique is frequently.preferredythecatalyst then being' in powdered form, for example 4010 100 mesh, andsuspended in -;llh hydI'OCaI bGIl'1S6lVeI1t. A'pressure sufiicient tomainvtain the solvent: in the liquid'phase is preferably employed,

:for; example 200 to -7 00*p.s.i. When employing a suspended catalyst, apreferred polymerization temperature range is 200 to325-F. While it ispreferred'to employ solid polymers produced accordance with the methodof Hogan and Banks as 5; 4 tion to employ polymers of ethylene producedby other methods so:long as the polymers have the properties ofIdensityand crystallinity as discussed above. For-example, suitableethylene polymers for use in thepractice 'of fthis'invention can beproduced by contacting ethylene ;erties and prepared as describedhereinafter, are used to-line the interior of -the-storage vessel. -Thenovel ethylene polymers used as a lining material in accordance withthis invention have a crystallinity of at least 70 percent, preferablyat 'least '80 percent, and more desir--determinedpreferablyibyemeasurements of nuclear magmetic-resonance(Wilson and 'Pake,".lournal of ,Polymer Science 10, 503 (1953)), using asample of-polymer which is in a state approaching equilibrium at 25 C Anapproach to this equilibrium state can be achieved by.

described hereinabove, it is within the scope of the invenwi tha'eatalyst comprising a mixture of an organometallic "compound, such as atrialkylaluminum, for example, triethylaluminum or triisobutylaluminum,and halides of "frnetals of gr up IV of the periodic system, such astitaniuin'or zirconium tetrachloride. Suitable solid poly- "mers'of'e'thylene can be produced by contacting ethylene ablyfat leastpercent, at 25 C. The crystallinity is jw yst c il i all ofganometflllichalide, Sill-CV11 as diethylaluminum chloride and/or ethylaluminumdichloride, and a group IVinetal halide such as titanium or zirconiumtetrachloride.

A more complete understanding of the invention may be obtained referringto the following description and the drawing which is an elevationalView, partly in section, illustrating a chemically resistant, linedcontainer 65 in accordance with the instant invention. While theinstantinvention is described Withrelation to lined, metal containers,it'is to be understood that vessels or "tanks constructed or othermaterials, e.g., concrete, wood, or glass, ean be lined with the highdensity, crystalline polymer described herein so as to provide improved,chemically "resistant containers.

Referring now to the drawing, there is illustrated a 'kerosenes, motoroils, and the like.

container 9 comprising a closed shell 10 and a liquid fuel' controlmeans as shown. 'The interior of the shell and the inlet and outletconduits are provided with a lining I 13 of a polymer of ethylene havingthe propertieslde scribed hereinbefore and preferably prepared inaccordance with the above-described Hogan and Banks process. In somecases, it may be desirableto line both the interior and exterior of avessel with the polymer.

in contact with the material to be stored or with other material whichmight attack those surfaces. Since the polymer can be applied to theinterior of the shell by This is particularly desirable when theexterior surfaces come several conventional processes described in theliterature,

it is not intended to limit the invention to any particular method ofapplication. One suitable method for applying the polymer lining is by aflame-spraying process in which the ethylene polymer in the form of apowder is sprayed through a flame to form a continuous coating on theinner surface of the container. Another suitable process is that ofwhirlor cyclone-sintering, which consists essentially of dipping thepreheated container into a fluidized bed of finely divided polymer. Thisfluidized bed is generally obtained by forcing a gas under pressurethrough the porous bottom of a vessel holding the polymer powder. In thecase of large tanks which do not adapt themselves to either of theforegoing methods, liners can be fabricated from sheets of the polymerand mechanically fastened to the tanks with studs or rivets. Thethickness of the lining can be varied as desired; however, a lining fromto Ms" thick is generally suitable although greater and smallerthicknesses can be used. As well as protecting the metal surfaces of thecontainer, the lining imparts added strength to the container because ofthe superior physical properties of the polymer used as the liningmaterial.

Since the ethylene polymers produced by the above- .described Hogan andBanks process are affected to a greater or lesser extent by the actionof oxygen when exposed thereto in the presence of light and/or heat, asuitable antioxidant is generally-added to the polymer prior to its useas described herein. While it is not intended to limit the invention toany particular antioxidation agent, it is preferred to use anantioxidant selected from the class consisting of alkyl substitutedphenols. Examples of these alkyl substituted phenols include 2,4,5-trimethylphenol; 2,6-diethyl-4-methylphenol;2,4-dimethyl-6-tertiarybutylphenol; 2,4-dimethyl-6-tertiaryoctylphenol;2,6-ditertiarybutyl-4-methylphenol; 2,6-ditertiaryamyl-4-hexylphenol;2,4,6-tritertiarybutylphenol; 2,6-ditertiaryamyl-4-methylphenol, and thelike.

The novel, chemically resistant container of this invention can beadvantageously used in the handling and storage of fuels, such as rocketfuels, jet fuels, gasolines, However, it has been found that a containerlined with polyethylene as described herein is particularly suitable forthe storage and handling of fuels containing amines, including primary,secondary and tertiary amines. The container of this invention isparticularly applicable to the storage and handling of fuels containingtertiary diamines. Specific examples of, but not exhaustive of; primaryamines are ethylamine, aniline, n-propylamine, isopropylamine,n-butylamine, 2-aminobutane, Z-aminopentane, 1,2 diaminoethane, 1,3diaminopropane. Secondary amines include dimethylamine, diethylamine,methylethylamines, dibutylamine, dipropylamine, diisopropylamine,

diallylamine, diphenylamine, dibenzylamine, di-(4-methylphenyl)-amine,and the like. Specific examples of tertiary amines includetriethylamine, tri-n-propylamine, Hi-

ethanolamine, and the like. Specific examples of tertiary diamines towhich this invention is particularly applicable includediamino-l-alkenes represented by the following structural formulaaralkyl radicals, and said Rs can be alike and unlike; n is an integerselected from the group consisting of 0,

' 1 and 2; the number of carbon atoms in R does not exceed 18; and thetotal number of carbon atoms in the molecule does not exceed 30.Included among the components corresponding to the above formula areN,N,N,N '-tetramethyl-1,Z-diaminoethylene, N,N,N',N'-tetramethyl-1,2-diamino-l-butene, N,N dimethyl-N,N-diallyl-l,Z-diaminoethylene, N,N-dimethyl-N,N-diethyl-1,2-diaminoethylene, N,N,N,N'-tetrabutyl-1 ,3-diaminopropene,N,N,N',N'-tetramethyl-1,2-diamino-3,3-dimet..yl-

l-butene, N,N,N',N-tetrabutyl-l,4-diamino-l-pentane,

-N,N,N,N tetraethyl 1,2 diamino 1- octadecylene,

N,N,N,N-tetramethyl-1,4-diamino-l-butene, N,N,N",N'-tetraethyl-1,Z-diamino-l-propene, N,N,N,N-tetraethyl- 1,3 diamino 4,4dimethyl 1 pentene, N,N,N',N' tetrabutyl 1,2 diamino 5 cyclohexyl lpentene, N,N,N,N' tetramethyl 1,2 diamino -'7 phenyl 1 octene,N,N,N',N-tetraethyl-1,2-diamino-3-(2-cyclohexenyl)-l-propene,N,N,N',N'-tetramethyl-l.3-diamino-2- (4-methylphenyl)-1-propene,N,N,N'.N-tetramethyl-l,3- diamino-4-hexyl-l-tetradecene,N,N,N',N'-tetraphenyl-l, 2- diaminoethylene, N,N,N,N tetracyclohexyl 1,2diamino-3,3-dimethyl-l-butene,N,N,N',N-tetra-(4-methylphenyl)-l,2-diaminoethylene,N,N,N',N-tetrabenzyl-l, Z-diaminoethylene andN,N,N',N'-tetramethyl-1,2-diamino-3,7-dimethyl-l,7-octadiene. 4 I

Fuels containing other amines such as tertiary triamines, can also bestored and handled with advantage in the container of this invention.Examples of'these latter compounds include N,N,N',N',N",N-hexamethyl-1,2,3-triaminopropane and the corresponding'hexaethyl, hexapropyl,hexabutyLhexaphenyl and hexabenzyl 1,2,3- triaminopropanes;N,N-dimethyl-N '.N,N,N"-tetraallyl- 1,2,3-triaminopropane;N-methyl-N-phenyl-N,N',N",N"- tetraethyl-1,2,3-triaminopropane; and N,NN',N',N",N" hexaallyl-1,2,3-triaminopropane, and the like. v

A more comprehensive understanding of the invention can be obtained byreferring to the following illustrative example, which is not intended,however, to be unduly limitative of the invention.

EXAMPLE 1 A series of tests were carried-out to show the effect of threedifferent tertiary diamines on high density, crystalline polyethyleneprepared as described herein as'com- 'pared to the effect of the samematerials on commercial polyethylene The commercial polyethylene usedwas ing about 2.5 weight percent chromium as chromium oxide. Prior toits use in the polytncrizatiomthe catalyst was activated by heating forseveral hours in a stream of anhydrous air at about. 950 F. The polymerof ethylene so prepared had properties approximately equal 1. 0.89 setout hereinbelow in Table'I'.

I claim:

1. A package comprising a container shell, a lining applied to the innersurface of said shell, said lining being formed of a solid polymer ofethylene having a density of at least 0.94 at 25 C. and a crystallinityof at least 70 percent at 25 C., and a liquid fuel containing amines incontact with said lining.

2. A chemically resistant package in accordance With claim 1 in whichsaid polymer of ethylene has a density Table I Softening temperature,FL; 260 Density 0.96 Injection molded:

Tensile strength, p.s.i. 5100 5 Elongation, percent 3 28 Compressionmolded:

Tensile strength, p.s.i 4200 Elongation, percent 20 Stiifness,p.s.i.140,000

Melt index 5 0.6 Impact strength, Izod 6 (ft. lbs/in. notch) 3.0 Heatdistortion, FF 165 Crystallinity, percent above 92 Ada ted from methodof Karrer, Davis and Dietrich, Ind. &Eng. hem. gAnal. Ed.) 2, 96 (1930).

4 ASTM D 747-50. ASTM D 1238-52T. ASTM D 25654T. 7 ASTM D 648-451.

Strips of samples of commercial polyethylene and of the high density,crystalline polyethylene were placed in glass bottles containingtertiary diamines, as named in Table II hereinbelow, and stored for 90days under nitrogen or oxygen. The results of these tests are set out inTable II.

of at least 0.95 at 25 C., and a crystallinity of at least 90 percent at25 C.

3. A package comprising a container shell, valved inlet and outletconduit means attached to said shell, a lining applied to the interiorsurfaces of said shell and conduit means, said lining being formed of asolid polymer of ethylene having a density of at least 0.95 at 25 C. anda crystallinity of at least 90 percent at 25 C., and a liquid fuelcontaining amines in contact with said lining.

4. The package of claim 3 in which the fuel contains tertiary diamines.

5. The package of claim 4 in which the fuel containsN,N,N,N-tetramethyl-1,3-diamino-1-butene.

6. The package of claim 4 in which the fuel containsN,N,N,N,-tetramethyl-1,3-diarnino-l-butene.

7. The package of claim 4 in which the fuel containsN,N,N',N-tetramethyl-1,3-diaminobutane.

Table 11 Commercial High Density, Crystal- Polyethylene linePolyethylene Fuel Stored Stored Stored Stored under N21 under Air 1under N1 under Air 90 Days 90 Days 90 Days 90 Days 1. N ,N,N,N'-tetramethyl-1,3-diaminol-propene:

Sample weight, percent increase 16. 8 15. 9 2. 9 3. 2

Sample size, persent increase- Thickness 12. 9 12. 9 None None 5. 6 20.0None N one 1. 9 4. 6 None None Sample weight, percent increase 17. 4 18.7 9. 6 4.1

Sample size, percent increase- Thickness 16. 1 12. 9 None None Widt 4.44.4 None None Length. 5. 0 5. 0 None None 8. N,,N,N'-tetraznethyl-1,3-diaminebutane:

Sample weight, percent increase--. 25. 0 24. 4 2. 9 2. 1

Sample Size, percent increase- Thickness. 19.3 19. 3 None None 11. 1 10.3 None None 7. 6 6. 9 None N one ethylene was discolored a dark yellow.

The data in Table II show that in the case of the commercialpolyethylene there was considerable swelling and weight gain. On theother hand, in the case of the high density, crystalline polyethylene,no swelling and a substantially smaller weight gain were noted.Furthermore, there were no indications that the fuels attacked the highdensity, crystalline polyethylene as occurred in the case of thecommercial polyethylene.

From the foregoing, it is seen that in accordance with this invention, anovel, chemically resistant, lined container is provided which isparticularly suitable for the storage of fuels. It will be apparent thatmany modifications and variations of the instant invention can be madeby those skilled in the art. Such variations and scope of the foregoingdisclosure.

floccuient material was observed ylene, the fuel turned cloudy and theglass bottles, and the poly- 60 mer'of ethylene having a density of atleast 0.94 at 25 C. and a crystallinity of at least percent at 25 C.,and a liquid fuel containing amines in contact with said lining.

References Cited in the file of this patent UNITED STATES PATENTS2,496,396 Kassel Feb. 7, 1950 2,712,384 Corneil July 5, 1955 2,822,357Brebner et a1. Feb. 4, 1958 2,825,721 Hogan et al. Mar. 4, 19582,833,755 Coover May 6, i958 November 24 1959 Patent No. 2,914,169

Vernon L, Moore It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correct-ion andthat the said Letters Patent should readas corrected below.

Column 6, line 23, fo nebutene read' fi i propene Signed and sealed this31st day of May 1960.

Attest:

KARL H. MINE Attesting Officer ROBERT C. WATSON Commissioner of Patents

8. AN ARTICLE OF MANUFACTURE COMPRISING A HOLLOW METAL CONTAINER, ALINING APPLIED TO THE INNER SURFACES OF SAID CONTAINER, SAID LININGBEING FORMED OF A SOLID POLYMER OF ETHYLENE HAVING A DENSITY OF AT LEAST0.94 AT 25* C. AND A CRYSTALLINITY OF AT LEAST 70 PERCENT AT 25*C., ANDA LIQUID FUEL CONTAINING AMINES IN CONTACT WITH SAID LINING.